On 18/01/2024 6:00 pm, Tomas Vondra wrote:
On 1/17/24 09:45, Konstantin Knizhnik wrote:
I have integrated your prefetch patch in Neon and it actually works!
Moreover, I combined it with prefetch of leaf pages for IOS and it also
seems to work.
Cool! And do you think this is the right design/way to do this?
I like the idea of prefetching TIDs in executor.
But looking though your patch I have some questions:
1. Why it is necessary to allocate and store all_visible flag in data
buffer. Why caller of IndexPrefetchNext can not look at prefetch field?
+ /* store the all_visible flag in the private part of the entry */
+ entry->data = palloc(sizeof(bool));
+ *(bool *) entry->data = all_visible;
2. Names of the functions `IndexPrefetchNext` and
`IndexOnlyPrefetchNext` are IMHO confusing because they look similar and
one can assume that for one is used for normal index scan and last one -
for index only scan. But actually `IndexOnlyPrefetchNext` is callback
and `IndexPrefetchNext` is used in both nodeIndexscan.c and
nodeIndexonlyscan.c
